- Removing vtkSelectionLink in favor of vtkAnnotationLink.

 - vtkAnnotationLayers now has a special "current" annotation.
   This annotation is used to store the current selection.

 - Updating lots of places that used the selection link to now
   use the annotation link.

 - Removing obsolete classes vtkGeoLineRepresentation (replaced by
   vtkRenderedSurfaceRepresentation) vtkTreeLayoutView (all functionality
   is in vtkGraphLayoutView) vtkSurfaceRepresentation (replaced by
   vtkRenderedSurfaceRepresentation).

 - The cache in the representation is now cleared when the ReleaseData
   flag is set in the pipeline.

 - Fixed warnings when selecting in empty graph view.

 - Fixed texture unit warnings in geoview.

 - Move selection type from view to representation.

 - Fixing geoview bug where nothing is rendered on the first render.
   We need to render once to initialize the graphics context, then
   'really' render the first time.

 - Need Render() to create render window in examples.